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<div class="box-shadow"></div>
.box-shadow {
    background-color: #FF8020;
    width: 200px;
    height: 200px;
    margin-top: -100px;
    margin-left: -100px;
    position: absolute;
    top: 50%;
    left: 50%;
}
.box-shadow:after {
    content: "";
    width: 180px;
    height: 1px;
    margin-top: 198px;
    margin-left: -90px;
    display: block;
    position: absolute;
    left: 50%;
    z-index: -1;
    -webkit-box-shadow: 0px 0px 10px 4px #000000;
       -moz-box-shadow: 0px 0px 10px 4px #000000;
            box-shadow: 0px 0px 10px 4px #000000;
}